Prop shop time for you. Prop shops sell and repair props. They also can have a loaner plan whereby the purchaser tests a prop and if its not right, they talk over the change necessary, you test the suggested prop and if it works you buy it. 2 caveats to that: Prop will be more expensive than purchased elsewhere (like they earned it......) and when you run a loaner prop you put it on, test it, take the data, immediately take it off, clean it up, put it back in the box and take it back to the store........because they will be expecting it to be in new condition for the next potential customer.